Nanowire Frontiers: Materials and Devices

申请人将开发III-V组半导体纳米线（NWs），用于三种应用——光伏、热电和β -光伏——都与能源生产有关。半导体NWs代表了一类新的材料，它将传统薄膜技术的二维特性扩展到下一代光电器件的三维。光伏（PV）设计的核心挑战是在太阳光谱中存在的非常广泛的波长范围内将太阳光转化为电能的成本效益。为了克服现有平板硅（Si）光伏电池的局限性，申请人正在开发有意设计的III-V半导体NWs，可以直接在硅太阳能电池上生长，以提高其效率。本课题将利用离轴电子全息技术来确定纳米碳纳米管中掺杂的物质，这是实现该技术的关键挑战之一，从而延续申请人对纳米碳纳米管PV的研究项目。虽然PV设备将有效地将可见光和近红外光转换为电能，但热电效应可以提供一种将较长红外波长转换为有用电能的方法。在其基于nw的光伏器件的工作过程中，申请人发现了半导体nw的新特性，即其与直径相关的光捕获特性和高效光热转换，这对热电发电机（teg）非常有用。在这个项目中，申请人正在进行的NW PV研究将扩展到使用垂直有序InSb纳米线阵列的teg，与现有设备相比，预计热电效率将大大提高。最后，贝塔伏打（BV）装置利用高能电子（贝塔粒子）在半导体中通过冲击电离产生电子-空穴对，从而直接产生电能。它们与PV设备相似，但用β粒子代替光子，因此是申请人PV研究的自然延伸。我们建议在Si衬底上制造磷化镓（GaP） NWs，通过提供比等效Si BV器件更高的β捕获效率和更大的电压来改进BV电池。这项研究可能的商业化带来了一个显著的好处——特别是纳米器件的开发，它可能为未来的能源技术带来优势。这项提案是加拿大成为世界上第一个开发颠覆性技术的机会，这些技术将在大型市场中产生竞争优势。该提案还将为希望在加拿大光电子行业建立职业生涯的年轻研究人员提供独特的培训机会，因为加拿大需要持续供应高素质人才（HQP）。

The applicant will develop group III-V semiconductor nanowires (NWs) for three applications - photovoltaics, thermoelectrics and betavoltaics - all related to energy generation. Semiconductor NWs represent a new class of materials that extends the two-dimensional nature of conventional thin film technologies into the third dimension for the next generation of optoelectronic devices. The central challenge in photovoltaic (PV) design is the cost-effective conversion of sunlight to electricity over the very broad range of wavelengths present in the solar spectrum. To overcome the limitations of existing flat panel silicon (Si) PV cells, the applicant is exploiting intentionally engineered III-V semiconductor NWs that can be grown directly on Si solar cells to boost their efficiency. This proposal will continue the applicant's research program on NW PV by using off-axis electron holography to ascertain the doping in NWs, which is one of the key challenges in realizing this technology. While PV devices will efficiently convert visible and near-infrared light into electrical power, the thermoelectric effect can provide a way to convert longer infrared wavelengths into useful electrical energy. During the course of his work on NW-based PV devices, the applicant discovered a new property of semiconductor NWs in their diameter-dependent light trapping properties and highly efficient photo-thermal conversion, which could be very useful for thermoelectric generators (TEGs). In this project, the applicant's ongoing NW PV research will be extended to TEGs using arrays of vertically ordered InSb nanowires, where the thermoelectric efficiency is predicted to be considerably higher compared to existing devices. Finally, betavoltaic (BV) devices use energetic electrons (beta particles) to create electron-hole pairs in a semiconductor by impact ionization for direct generation of electrical power. They are similar to PV devices but replace photons with beta particles, and are therefore a natural extension of the applicant's PV research. We propose to fabricate gallium phosphide (GaP) NWs on Si substrates for improved BV batteries by offering a higher efficiency of beta capture and larger voltage than equivalent Si BV devices. A significant benefit arises from likely commercialization of this research - in particular, development of nanodevices that might yield advantages for future energy technologies. This proposal is an opportunity for Canada to be the first in the world to develop disruptive technologies that will yield a competitive edge in large markets. This proposal will also provide a unique training opportunity for young researchers wishing to establish careers in the Canadian optoelectronics industry where a continual supply of highly qualified personnel (HQP) is needed.